Korean Patent Application Publication No. 10-2010-0066834 (hereinafter referred to as “prior invention 1”) discloses an optical communication device that switches an optical signal using a reflection output unit that is arranged in a portion of a main core and that forms a small angle. However, “prior invention 1” can be restrictively applied only to a structure for switching an optical signal to a waveguide forming a small angle because the reflection output unit branches from the main core at a small angle.
Further, Korean Patent Application Publication No. 10-2011-0055142 (hereinafter referred to as “prior invention 2”) discloses an optical switch structure using reflection in a grid-shaped optical transmission network. However, “prior invention 2” is problematic in that it is configured using a structure in which, after being reflected, an optical signal is transmitted in the direction of a straight line having a small angle with respect to a reference direction, that is, in a diagonal direction, thus making it impossible to transmit light in a vertical direction at a switching node.